cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations wchar/vswprintf.c -o wchar/vswprintf -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
wchar/vswprintf.c:5:75: error: ‘vswprintf’ undeclared here (not in a function)
    5 | int (*foo)(wchar_t *restrict, size_t, const wchar_t *restrict, va_list) = vswprintf;
      |                                                                           ^~~~~~~~~